Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Aussie Mike]

Another Environmental Disaster in the making...
Of course things like this just can't happen... ... until they do...

URGENT: Concerns of core partially melting at Fukushima nuke plant

TOKYO, March 12, Kyodo

The core at Fukushima No. 1 nuclear power plant's No. 1 reactor may be partially melting, the nuclear safety agency said Saturday.

Radioactive substance cesium was detected around the reactor, it said.

==Kyodo

======================================
'1,000 dead' in Japan quake; nuke plants overheat
More than 1,000 people were feared dead and authorities warned a meltdown may be under way at a nuclear plant after a monster tsunami devastated a swathe of northeast Japan.

Reactor cooling systems failed at two generating plants after Friday's record 8.9-magnitude earthquake hit, unleashing a terrifying 10-metre (33-foot) high wave that tore through coastal towns and cities, destroying all in its path.

Radiation 1,000 times above normal was detected in the control room of one nuclear plant, although authorities said levels outside the facility's gates were only eight times above normal, spelling "no immediate health hazard."

But officials warned one of the plants, just 250 kilometres northeast of Tokyo, "may be experiencing nuclear meltdown," Kyodo and Jiji reported.

Tens of thousands of people were evacuated from around the plants as Tokyo Electric Power, which runs the facilities, said it had released some radioactive vapour at both locations to relieve building reactor pressure.

"We are not in a situation in which residents face health damage," Chief Cabinet Secretary Yukio Edano told reporters, according to Jiji news agency.

The two nuclear plants affected are the Fukushima No. 1 and No. 2 plants, both located about 250 kilometres (160 miles) northeast of Tokyo.

The atomic emergency came as the country struggled to assess the full extent of the devastation wreaked by the massive tsunami, which was unleashed by the strongest quake ever recorded in Japan off the eastern coast.

[Aussie Mike]

Reuters/KYODO/Files
By Scott DiSavino

NEW YORK | Fri Mar 11, 2011 9:55pm EST

NEW YORK (Reuters) - Japanese officials may only have hours to cool reactors that have been disabled by Friday's massive earthquake and tsunami or face a nuclear meltdown.

Tokyo Electric Power Co (TEPCO) (9501.T) is racing to cool down the reactor core after a highly unusual "station blackout" -- the total loss of power necessary to keep water circulating through the plant to prevent overheating.

Daiichi Units 1, 2 and 3 reactors shut down automatically at 2:46 p.m. local time due to the earthquake. But about an hour later, the on-site diesel back-up generators also shut, leaving the reactors without alternating current (AC) power.

That caused Tepco to declare an emergency and the government to evacuate thousands of people from near the plant. Such a blackout is "one of the most serious conditions that can affect a nuclear plant," according to experts at the Union of Concerned Scientists, a U.S. based nuclear watchdog group.

"If all AC power is lost, the options to cool the core are limited," the group warned.

TEPCO also said it has lost ability to control pressure at some of the reactors at its Daini plant nearby.

The reactors at Fukushima can operate without AC power because they are steam-driven and therefore do not require electric pumps, but the reactors do require direct current (DC) power from batteries for its valves and controls to function.

If battery power is depleted before AC power is restored, the plant would stop supplying water to the core and the cooling water level in the reactor core could drop.

RADIATION RELEASE

Officials are now considering releasing some radiation to relieve pressure in the containment at the Daiichi plant and are also considering releasing pressure at Daini, signs that difficulties are mounting. Such a release has only occurred once in U.S. history, at Three Mile Island.

"(It's) a sign that the Japanese are pulling out all the stops they can to prevent this accident from developing into a core melt and also prevent it from causing a breach of the containment (system) from the pressure that is building up inside the core because of excess heat," said Mark Hibbs, a nuclear expert at the Carnegie Endowment for International Peace.

While the restoration of power through additional generators should allow TEPCO to bring the situation back under control, left unchecked the coolant could boil off within hours. That would cause the core to overheat and damage the fuel, according to nuclear experts familiar with the Three Mile Island accident in Pennsylvania in 1979.

It could take hours more for the metal surrounding the ceramic uranium fuel pellets in the fuel rods to melt, which is what happened at Three Mile Island. That accident essentially frozen the nuclear industry for three decades.

Seven years later the industry suffered another blow after the Chernobyl plant in Ukraine exploded due to an uncontrolled power surge that damaged the reactor core, releasing a radioactive cloud that blanketed Europe.

The metal on the fuel rods would not melt until temperatures far exceed 1,000 degrees F. The ceramic uranium pellets would not melt until temperatures reached about 2,000 degrees F, nuclear experts said.

[Andy72]

Don't believe everything you read.....

This following is brilliant.. and written by a Japanese (I get also fresh news from the Japanese wife of a colleague of mine.. she is in Nagoya.. a bit closer than us!):
http://squeeze-box.ca/?p=785